Composite materials are frequently used in the most diverse areas and consist mainly of plastic with embedded fiber reinforcement. The fiber reinforcement can for example take the form of tapes, fabrics, felts and mats. For example, coachwork parts of polyester resin reinforced with glass fibers and plastics such as epoxy resin reinforced with carbon fibers are frequently used in motor car construction and numerous further components such as consoles and cladding are likewise manufactured from such composite materials. When using carbon fibers as a reinforcement, fabrics of carbon fibers are frequently used because one can then obtain a reinforcement in all directions of the component.
The field of composite materials is however in no way restricted to glass fibers and carbon fibers there are many other reinforcement fibers which can be considered. Furthermore, the most diverse plastics can also be used as a matrix material. All such materials are described here generically as composite materials or fiber reinforced plastics. They can also be described by the generic term “organic sheet metals”. This term is understood in some circles as a specialist term. The present invention primarily uses those composite materials which use a thermoplastic material, i.e. a thermoplastic as matrix material which softens or becomes pasty at elevated temperatures below the melting point. It is, however, not precluded that duroplastics can also be used as a matrix material provided these are adequately soft or become soft or pasty at elevated temperature, i.e. at temperatures which lie beneath the temperatures at which the matrix material or the component is permanently damaged. The method claimed here can also be used for composite materials with matrix materials which are indeed not thermoplastics but have not yet reached their final state but rather are present in a state in which they soften with or without heating but which can be transferred into a harder state in the course of time or by the action of ultraviolet light or humidity or otherwise through progressive polymerization or cross-linking.
It is frequently necessary to use components of composite materials with fastener elements, for example in order to secure the corresponding components to other parts or to attach other parts to the fiber reinforced plastic components.
Both rivet elements and also bolt or nut elements can be considered which can all be subsumated under the term functional elements. This term applies also for clips and bearings which can likewise be secured to composite materials. Irrespective of what form such functional elements have it is always necessary to provide a hole or a plurality of holes in a plastic part in order to enable the attachment of the respective desired functional element, unless threaded inserts or eyes are integrated into the plastic component during the manufacture of the component, which is however very time consuming and complicated and leads to further costs and sometimes makes a local thickening of the plastic part necessary. The manufacture of holes is mainly achieved by a drilling process, whereby material residues such as cuttings arise and the composite material is weakened in the region of the bore.
It is conceivable to subject the component to a punching process in order to generate a hole, whereby waste in the form of punching slugs which has to be dispensed of arises as well as a local weakening of the component.
Composite materials consist of any desired reinforcement material or fibers and any desired plastically deformable or meltable matrix material. The term “composite materials” as used here in accordance with the invention includes therefore not only plastics with fiber reinforcement but, for example, also matrix materials of metal, for example aluminum, with a reinforcing material, such as for example carbon fibers or ceramic particles.